Add Analog Devices AXI PWM generator.

Link: https://analogdevicesinc.github.io/hdl/library/axi_pwm_gen/index.htmlSigned-off-by: Drew Fustini <dfustini@baylibre.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Co-developed-by: Trevor Gamblin <tgamblin@baylibre.com>
Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/20240605203507.1934434-2-tgamblin@baylibre.comSigned-off-by: Uwe Kleine-König <ukleinek@kernel.org>